Class: LogStash::Inputs::Syslog

Inherits:
Base show all
Defined in:
lib/logstash/inputs/syslog.rb

Overview

Read syslog messages as events over the network.

This input is a good choice if you already use syslog today. It is also a good choice if you want to receive logs from appliances and network devices where you cannot run your own log collector.

Of course, ‘syslog’ is a very muddy term. This input only supports RFC3164 syslog with some small modifications. The date format is allowed to be RFC3164 style or ISO8601. Otherwise the rest of the RFC3164 must be obeyed. If you do not use RFC3164, do not use this input.

Note: this input will start listeners on both TCP and UDP

Constant Summary

Constants included from Config::Mixin

Config::Mixin::CONFIGSORT

Instance Attribute Summary

Attributes inherited from Base

#params, #threadable

Attributes included from Config::Mixin

#config, #original_params

Attributes inherited from Plugin

#logger, #params

Instance Method Summary collapse

Methods inherited from Base

#tag

Methods included from Config::Mixin

#config_init, included

Methods inherited from Plugin

#eql?, #finished, #finished?, #hash, #inspect, lookup, #reload, #running?, #shutdown, #terminating?, #to_s

Constructor Details

#initialize(params) ⇒ Syslog

Returns a new instance of Syslog.



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# File 'lib/logstash/inputs/syslog.rb', line 48

def initialize(params)
  super
  @shutdown_requested = false
  BasicSocket.do_not_reverse_lookup = true
end

Instance Method Details

#register ⇒ Object 



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# File 'lib/logstash/inputs/syslog.rb', line 55

def register
  @grok_filter = LogStash::Filters::Grok.new(
    "overwrite" => "message",
    "match" => { "message" => "<%{POSINT:priority}>%{SYSLOGLINE}" },
  )

  @date_filter = LogStash::Filters::Date.new(
    "match" => [ "timestamp", "MMM  d HH:mm:ss", "MMM dd HH:mm:ss", "ISO8601"]
  )

  @grok_filter.register
  @date_filter.register

  @tcp_clients = ThreadSafe::Array.new
end

#run(output_queue) ⇒ Object 



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# File 'lib/logstash/inputs/syslog.rb', line 72

def run(output_queue)
  # udp server
  udp_thr = Thread.new do
    begin
      udp_listener(output_queue)
    rescue => e
      break if @shutdown_requested
      @logger.warn("syslog udp listener died",
                   :address => "#{@host}:#{@port}", :exception => e,
                   :backtrace => e.backtrace)
      sleep(5)
      retry
    end # begin
  end # Thread.new

  # tcp server
  tcp_thr = Thread.new do
    begin
      tcp_listener(output_queue)
    rescue => e
      break if @shutdown_requested
      @logger.warn("syslog tcp listener died",
                   :address => "#{@host}:#{@port}", :exception => e,
                   :backtrace => e.backtrace)
      sleep(5)
      retry
    end # begin
  end # Thread.new

  # If we exit and we're the only input, the agent will think no inputs
  # are running and initiate a shutdown.
  udp_thr.join
  tcp_thr.join
end

#syslog_relay(event) ⇒ Object 



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# File 'lib/logstash/inputs/syslog.rb', line 197

def syslog_relay(event)
  @grok_filter.filter(event)

  if event["tags"].nil? || !event["tags"].include?("_grokparsefailure")
    # Per RFC3164, priority = (facility * 8) + severity
    #                       = (facility << 3) & (severity)
    priority = event["priority"].first.to_i rescue 13
    severity = priority & 7   # 7 is 111 (3 bits)
    facility = priority >> 3
    event["priority"] = priority
    event["severity"] = severity
    event["facility"] = facility

    event["timestamp"] = event["timestamp8601"] if event.include?("timestamp8601")
    @date_filter.filter(event)
  else
    @logger.info? && @logger.info("NOT SYSLOG", :message => event["message"])

    # RFC3164 says unknown messages get pri=13
    priority = 13
    event["priority"] = 13
    event["severity"] = 5   # 13 & 7 == 5
    event["facility"] = 1   # 13 >> 3 == 1
  end

  # Apply severity and facility metadata if
  # use_labels => true
  if @use_labels
    facility_number = event["facility"]
    severity_number = event["severity"]

    if @facility_labels[facility_number]
      event["facility_label"] = @facility_labels[facility_number]
    end

    if @severity_labels[severity_number]
      event["severity_label"] = @severity_labels[severity_number]
    end
  end
end

#teardown ⇒ Object 



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# File 'lib/logstash/inputs/syslog.rb', line 165

def teardown
  @shutdown_requested = true
  close_udp
  close_tcp
  finished
end